MASTER OSCILLATOR POWER AMPLIFIER (MOPA)A transmitter in which the
oscillator is isolated from the antenna by a power amplifier.
MICROPHONEAn energy converter that changes sound energy into electrical energy.
MODULATED WAVEA complex wave consisting of a carrier and a modulating wave that is
transmitted through space.
MODULATING WAVEAn information wave representing intelligence.
MODULATION FACTOR (M)An indication of relative magnitudes of the rf carrier and the
MODULATION INDEXThe ratio of frequency deviation to the frequency of the modulating
MODULATIONThe ability to impress intelligence upon a transmission medium, such as radio
MODULATORThe last audio stage in which intelligence is applied to the rf stage to modulate
MULTIPLICATION FACTORThe number of times an input frequency is multiplied.
MULTIVIBRATOR MODULATORAn astable multivibrator used to provide frequency
modulation by inserting the modulating af voltage in series with the base-return of the
NEGATIVE ALTERNATIONThat part of a sine wave that is below the reference level.
NONLINEAR DEVICEA device in which the output does not rise and fall directly with the
NONLINEAR IMPEDANCEAn impedance in which the resulting current through the device
is not proportional to the applied voltage.
OVERMODULATIONA condition that exists when the peaks of the modulating signal are
PEAK AMPLITUDEThe maximum value above or below the reference line.
PEAK DETECTIONDetection that uses the amplitude of pam or the duration of pdm to
charge a holding capacitor and restore the original waveform.
PEAK POWERThe maximum value of the transmitted pulse.
PERCENT OF MODULATIONThe degree of modulation defined in terms of the maximum
permissible amount of modulation.
PERIODThe duration of a waveform.
PHASE MODULATION (pm)Angle modulation in which the phase of the carrier is
controlled by the modulating waveform. The amplitude of the modulating wave determines
the amount of phase shift and the frequency of the modulation determines how often the